This invention relates to a valve plate for a thermostatic valve comprising a basic body shaped as a sheet metal preform whose edge is provided with a surrounding ring groove in which a sealing ring is provided which is assigned to a valve seat.
A valve plate of the initially mentioned type is known (German Utility Patent DE 91 00 356), in which an O-ring is provided as a sealing ring. It is further suggested in the Utility Patent to provide the exterior edge of the surrounding ring groove with a section which extends in parallel to the stamping direction and to bend it again after the inserting of the sealing ring so that it surrounds a sealing ring, particularly a sealing ring with a non-circular cross-section, in a form-locking manner. It was found that it is relatively difficult to securely hold a sealing ring with a circular cross-section in the ring groove without any additional measures because the occurring flow forces have the effect of loosening the sealing ring out of its ring groove. This problem can be eliminated by means of the suggestion of providing the grooves with an exterior edge which is to be bent subsequently and which surrounds a sealing ring, particularly a sealing ring with a non-circular cross-section, in a form-locking manner. However, in order to be able to hold a sealing ring in a form-locking manner, it must receive a special shape which is connected with higher expenditures with respect to the manufacturing and therefore makes the sealing ring more expensive.
It is an object of the invention to provide a valve plate of the initially mentioned type in the case of which a sealing ring of a simple design is held in a sufficiently secure manner even when relatively high flow forces occur.
This object is achieved in that the ring groove has an interior boundary wall, a bottom and an exterior boundary wall, and in that the exterior boundary wall of the ring groove is bent toward the inside and, together with the bottom of the ring groove, encloses an angle of less than 90.degree. into which the sealing ring penetrates which has an essentially rectangular cross-section, protrudes in the axial direction toward the outside beyond the exterior boundary wall, and is situated opposite the valve seat by means of its surrounding edge.
A sealing ring with a rectangular cross-section can be manufactured in a simple and low-cost manner because it can be cut off a hose; that is, it represents a short hose piece. The bent edge penetrating into the sealing ring securely holds the sealing ring also in the case of relatively high flow forces. Furthermore, the surrounding edge of the sealing ring, which is situated opposite the valve seat, provides a good sealing without the requirement of a relatively significant elastic deforming of the sealing ring.
In a further development of the invention, it is provided that the interior edge of the exterior boundary wall of the ring groove is rounded or bevelled. As a result, it is achieved that the interior edge of the exterior boundary wall which enters into the sealing ring does not damage the sealing ring.
In a further development of the invention, it is provided that the exterior boundary wall of the ring groove is shorter than the interior boundary wall which corresponds at least to the axial height of the sealing ring. Thus, it is achieved that the interior boundary wall supports the sealing ring in the radial direction so that, when placed against the valve seat, it is compressed and does not yield elastically.